Field of the Invention
The present invention relates to a workpiece changer for a machine tool with Stool spindle into which the tools can be clamped for machining workpieces, with two wheels which are arranged parallel to one another and which are rotatable about an axis of rotation into at least two angular positions, at least two swivel tables for clamping workpieces, the swivel tables being arranged between the wheels and mounted in a swivelling manner on said wheels, each about a respective swivel axis, which swivel axis runs parallel to the axis of rotation, and wherein in each angular position one of the swivel tables is located in its working position in which clamped workpieces can be machined with the tools.
Related Prior Art
Such a workpiece changer is known, for example, from DE 35 05 138 C2.
The known and other workpiece changer can in principle be used with vertical or horizontal tool spindles, wherein the tool spindles can be moved relative to the workpiece changer in the three orthogonal spatial axes X, Y and Z. Moreover, the working spindle can be mounted in a swivelling manner about one of the spatial axes.
Devices with which the workpieces to be machined are clamped are arranged on the at least two swivel tables so that they are available for machining.
While one of the swivel tables is in its working position, in which the workpiece clamped on it is machined, the other swivel table is located in a position in which a finished machined workpiece can be removed and a new workpiece to be machined can be clamped.
Both swivel tables are each mounted in a swivelling manner between the wheels so that a clamped workpiece can point upwards both in the working position and in the position in which workpieces are changed. For this purpose, it is necessary that, in the case of each change of workpiece, each swivel table is rotated 180° between the wheels.
The swivel axis of the swivel tables can furthermore be used as a further machine axis so that, during machining of the workpieces, these can be provided to the tool in a different angular alignment about the X-axis.
In order to increase the flexibility of machining, the tool spindle can be swivelled about an axis which runs transversely to the swivel axis so that oblique machining of the workpieces is also possible from this direction.
In general, the three orthogonal axes are realized in the tool spindle which is arranged in a spindle head which is arranged, where necessary in a swivelling manner, on a stand and is adjustably on the stand in the direction of the longitudinal axis of the tool, i.e. the Z-axis. This stand enables movement in the two other spatial directions, i.e. in the X and Y direction.
It is also known in the case of machining of very long structural parts to move the workpiece changer in the direction of the swivel axes and the axis of rotation of the wheels, i.e. in the X direction with respect to the tool spindle, i.e. to realize at least one axis in the workpiece.
When the workpiece clamped on the swivel table located in the working position has been machined, the wheels are rotated about the axis of rotation by 180° so that the other swivel table is now located in its working position and the workpiece which has just been machined can be replaced by a workpiece still to be machined.
For the purpose of this change of workpiece, the two wheels are rotated synchronously with one another about 180° so that they are rotated from their first angular position, in which one swivel table is in its working position, into their other angular position, in which the other swivel table is located in working position.
It is also known to equip such a workpiece changer not with two, but rather, for example, with four swivel tables so that the swivel tables are arranged on the wheels offset with respect to one another by 90°. The workpiece changer correspondingly then has four designated angular positions for its wheels in which in each case one of the swivel tables is located in its working position.
Although the known workpiece changers have proved useful in many applications, the machine tools fitted with them are very large, particularly in cases where large structural components which also have a corresponding length in the x direction of, for example, 3 m are supposed to be machined on them.
In particular when machining of the workpieces is supposed to be carried with a double spindle into which therefore two machining tools are inserted which machine the workpiece located in the working position independently of one another, the overall dimensions of the known workpiece change table are so large that a machine tool in the cabin or housing of which the workpiece changer is set up has a very large volume.